Fail safe mechanism for valve using a cock and lock return spring

Abstract

A fail safe mechanism having a return member, valve stem extension, energy storage member, and locking assembly. The valve stem extension is driven by an electrical actuator and configured to drive the return member in a first direction and to be driven by the return member in a second direction. The energy storage member is configured to store energy when the electrical actuator causes the valve stem extension to drive the return member in the first direction and to release the energy stored therein when a disruption of power causes the return member to drive the valve stem extension in the second direction. The locking assembly is configured to hold the return member in a cocked position such that the valve stem extension rotates with the valve independently of the return member and free of influence from the energy storage member while the power is applied to the electrical actuator.

1. A fail safe mechanism for a valve having a fail safe position and positioned by an electrical actuator, comprising:
 a return member; 
 a valve stem extension operably coupled to the valve and driven by the electrical actuator, the valve stem extension configured to drive the return member in a first direction toward a cocked position and to be driven by the return member in a second direction thereby moving the valve toward the fail safe position; 
 an energy storage member operably coupled between the return member and an anchor, the energy storage member configured to store energy when the electrical actuator causes the valve stem extension to drive the return member in the first direction and to release the energy stored therein when a disruption of power causes the return member to drive the valve stem extension and the valve in the second direction; and 
 a locking assembly configured to hold the return member in the cocked position such that the valve stem extension rotates with the valve independently of the return member and free of influence from the energy storage member while power is applied to the electrical actuator. 
 
   
   
     2. The fail safe mechanism of  claim 1 , wherein the locking assembly is configured to release the first member from the cocked position upon the disruption of the power. 
   
   
     3. The fail safe mechanism of  claim 1 , wherein the return member and the valve stem extension are engaged with each other through a groove and pin interaction, and wherein the energy storage member comprises a plurality of elongate extension springs. 
   
   
     4. The fail safe mechanism of  claim 1 , wherein the fail safe mechanism further includes a mounting plate, the mounting plate planar with the return member and the valve stem extension and providing the anchor. 
   
   
     5. The fail safe mechanism of  claim 1 , wherein the energy storage member is an elongate extension spring, the elongate extension spring configured to be stretched as the first member moves toward the cocked position. 
   
   
     6. The fail safe mechanism of  claim 1 , wherein the first member is a first disk having a non-circular periphery and the valve stem extension is a second disk having a circular periphery. 
   
   
     7. The fail safe mechanism of  claim 1 , wherein the locking assembly includes an electric solenoid. 
   
   
     8. The fail safe mechanism of  claim 7 , wherein the locking assembly includes a lever pivot arm and a return spring, the return spring biasing one end of the lever pivot arm toward the electric solenoid. 
   
   
     9. The fail safe mechanism of  claim 7 , wherein the fail safe mechanism further includes a bracket assembly supporting the electric solenoid, the bracket assembly including a stop tab preventing the first member from rotating past the cocked position and a position switch identifying a maximum stop of the valve. 
   
   
     10. A fail safe mechanism for a valve having a valve stem driven into and between open and closed positions by an electrical actuator, comprising:
 a mounting plate; 
 a coupled disk rotatable relative to the mounting plate and operably connected to the valve stem, the coupled disk rotatably driven by the electrical actuator; 
 a segmented disk selectively engageable with the coupled disk, the segmented disk rotatably driven by the coupled disk when engaged therewith; 
 an energy storage member operably coupled to the segmented disk and the mounting plate, the energy storage member storing energy when the segmented disk is rotatably driven by the electrical actuator through the coupled disk toward a cocked position; 
 a locking assembly mounted to the mounting plate, the locking assembly locking the segmented disk in the cocked position until the electrical actuator experiences a disruption in power; and the valve stem rotates with the valve interpedently of the segmented disk and free of influence from the energy storage member while power is applied to the electrical actuator. 
 
   
   
     11. The fail safe mechanism of  claim 10 , wherein the locking assembly is configured to release the segmented disk from the cocked position upon the disruption in the power. 
   
   
     12. The fail safe mechanism of  claim 11 , wherein the segmented plate is able to engage and rotatably drive the coupled disk using the energy stored in the energy storage device when the segmented plate is released from the cocked position. 
   
   
     13. The fail safe mechanism of  claim 12 , wherein the coupled disk is able to drive the valve into a fail safe position when driven by the segmented disk. 
   
   
     14. The fail safe mechanism of  claim 10 , wherein the coupled disk rotates independently of the segmented disk after the segmented disk has been locked in the cocked position. 
   
   
     15. The fail safe mechanism of  claim 10 , wherein the coupled disk rotates independently of the segmented disk when the segmented disk is in the cocked position. 
   
   
     16. A fail safe mechanism for a valve rotatably driven into and between open and closed positions by an actuator, comprising:
 a mounting plate; 
 a coupled disk rotatable relative to the mounting plate, the coupled disk rotatably driven by the actuator; 
 a segmented disk selectively engageable with the coupled disk, the segmented disk rotatably driven by the coupled disk when engaged thereto; 
 an energy storage member operably coupled to the segmented disk and the mounting plate, the energy storage member storing energy when the segmented disk is rotatably driven by the coupled disk toward a cocked position; 
 a locking assembly mounted to the mounting plate, the locking assembly configured:
 to releasably lock the segmented disk in the cocked position such that the actuator is free to rotatably drive the valve into and between the open and closed positions without interference from the energy storage member, and 
 to release the segmented disk from the cocked position upon a disruption of power to the actuator to drive the valve to a fail safe position. 
 
 
   
   
     17. The fail safe mechanism of  claim 16 , wherein the locking assembly is configured to releasably lock the segmented disk in the cocked position such that the coupled disk is able to rotate free of the segmented disk; and wherein the energy in the energy storage member is employed to drive the segmented disk away from the cocked position when the disruption of power is experienced and the locking member has released the segmented disk from the cocked position, the segmented disk in turn driving the coupled disk to drive the valve to the fail safe position. 
   
   
     18. The fail safe mechanism of  claim 16 , wherein the coupled disk has an arcuate channel formed into a top surface along a periphery and the segmented disk includes a pin extending into the arcuate channel. 
   
   
     19. The fail safe mechanism of  claim 18 , wherein first and second portions of the pin project from generally opposing sides of the segmented disk, the first portion of the pin operably coupled to the energy storage member, the second portion of the pin traveling through the arcuate channel and engageable with an end wall of the arcuate channel. 
   
   
     20. The fail safe mechanism of  claim 19 , wherein the mounting plate is disposed within the valve.